Well this does make sense. If only one type of hardware device is in use, then `-init_hw_device` will suffice. However, if we use hardware filters with different device types, such as OpenCL, and we want to switch to a VideoToolbox filter later in the chain, we will have a issue. Since there is no `hwmap` between OpenCL and VideoToolbox, we need to perform a `hwdownload` followed by a `hwupload`. If the `derive_device` option cannot be used with `hwupload` due to `device_derive` not being implemented, the filter will struggle to find the correct device for uploading. It may attempt to upload to the OpenCL device without `device_derive` set if it comes after an OpenCL filter.
> On Feb 23, 2024, at 03:28, Mark Thompson <[email protected]> wrote: > > On 22/02/2024 18:46, gnattu via ffmpeg-devel wrote: >> There is no device context to be setup, nor devices to be >> selected with VideoToolbox. Just a simple return would allow >> us to use derived device in filters like >> `hwupload=derive_device=videotoolbox` >> Signed-off-by: Gnattu OC <[email protected]> >> --- >> libavutil/hwcontext_videotoolbox.c | 9 +++++++++ >> 1 file changed, 9 insertions(+) >> diff --git a/libavutil/hwcontext_videotoolbox.c >> b/libavutil/hwcontext_videotoolbox.c >> index fe469dc161..d13199eca7 100644 >> --- a/libavutil/hwcontext_videotoolbox.c >> +++ b/libavutil/hwcontext_videotoolbox.c >> @@ -759,6 +759,14 @@ static int vt_device_create(AVHWDeviceContext *ctx, >> const char *device, >> return 0; >> } >> +static int vt_device_derive(AVHWDeviceContext *device_ctx, >> + AVHWDeviceContext *src_ctx, AVDictionary *opts, >> + int flags) >> +{ >> + // There is no context to be setup with VT, just return. >> + return 0; >> +} >> + >> const HWContextType ff_hwcontext_type_videotoolbox = { >> .type = AV_HWDEVICE_TYPE_VIDEOTOOLBOX, >> .name = "videotoolbox", >> @@ -766,6 +774,7 @@ const HWContextType ff_hwcontext_type_videotoolbox = { >> .frames_priv_size = sizeof(VTFramesContext), >> .device_create = vt_device_create, >> + .device_derive = vt_device_derive, >> .frames_hwctx_size = sizeof(AVVTFramesContext), >> .frames_init = vt_frames_init, >> .frames_get_buffer = vt_get_buffer, > > This derivation behaviour doesn't make any sense inside libavutil. Features > which are only for the ffmpeg utility should be implemented inside the ffmpeg > utility. > > (Also, try -init_hw_device.) > > Thanks, > > - Mark > _______________________________________________ > ffmpeg-devel mailing list > [email protected] <mailto:[email protected]> > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > [email protected] <mailto:[email protected]> with > subject "unsubscribe". _______________________________________________ ffmpeg-devel mailing list [email protected] https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
